R129 is code for Mercedes SL-Class model
Code R129 identify Meredes-Benz SL-Class roadster produced 89-02.
Produced in 204,940 units, the two-door convertible with a soft and removable hard top, rear-wheel drive, and engines ranging from 2.8 to 7.3 liters represented the pinnacle of technological advancement at the time.
This classic car, which made a lasting mark on the automotive industry in the early 1990s and continues to excite modern car enthusiasts, combines incredible performance, cutting-edge technology, and a beautiful appearance. With the purpose of taking you on a tour of the Mercedes SL-Class R129 and highlighting its noteworthy features, background, and reasons for being considered a timeless classic, we republish this comprehensive guide.
R129 in between R107 and R230 models
The Mercedes-Benz W124's reduced floorpan served as the foundation for the 1984 design of the R129. Sales of the new SL-class were first offered in March 1989 at the Geneva Motor Show, with left-hand drive starting that summer and right-hand drive starting that fall. In the race for European Car of the Year, it finished second to the Citroen XM.
Tradition and Innovation
The convertibles from Mercedes-Benz have always set the standards for luxury sports cars. With the R129 SL on 89, not only has this tradition has been continued - a car has been created which is quite unique in the sum total of its features and qualities. On the one hand, the convertible has a dynamic appeal comparable to that of the legendary 300 SL from the fifties; on the other hand, it incorporates an abundance of innovative engineering features allowing the previously conflicting criteria of sporty handling and ride comfort to be reconciled without compromise. The R129 Mercedes-Benz convertibles, the 500 SL, 300 SL-24 and 300 SL with eight and six-cylinder engines developed 240 kW/326 hp, 170 kW/231 hp and 140 kW/190 hp respectively, offered a hitherto unequalled fascination of open driving in typical convertible style.
Comfort: electro-hydraulically operated soft top
To make open driving both pleasurable and comfortable, the convertible was fitted with an electro-hydraulically operated soft top, in addition to the standard hard top. At the push of a button, the soft top was opened and folded away under its cover or closed and locked within 30 seconds. During this process, the side windows were retracted and subsequently return to their initial position. To ensure that even the open car meat Mercedes-Benz's exacting safety standards, a completely new, extendable roll-over bar was developed at that time. When retracted, it is flushed with the soft top cover. When an electronic control unit registered a critical situation which might lead to a roll-over, the bar moved up within 0.3 seconds. It could also be extended at the push of a button. Another new feature for pleasurable open driving even at high speeds was the so-called draught-stop, a framed net attached to the roll-over bar which effectively reduced unpleasant draught inside the car. It also reduced wind noise to a minimum and in conjunction with the generously dimensioned heating system for the interior, it gone a long way towards significantly extending the "open-air season".
The performance was in keeping with the convertible's claim to sports-car characteristics. Depending on the model and transmission version, the new SL accelerated from standstill to 100 km/h in between 6.2 and 9.3 seconds, its top speeds ranged from 223 to 250 km/h.
The two six-cylinder models was fitted as standard with a five-speed gearbox, the 300 SL-24 was also available with a sporty gearbox version. A four-speed automatic transmission was optionally available for the two six-cylinder models and standard on the 500 SL because of the latter's exceptional power potential. A new feature on the automatic transmission was a special parking lock which ensured that the ignition key can only be removed when the parking lock has been engaged. Conversely, the parking lock could only be disengaged with the ignition key in drive position.
Refined emission control system
Like all other Mercedes-Benz petrol-engined cars, the SL models were fitted as standard with the closed-loop three-way catalytic converter. It was a completely newly developed double-fluted catalytic converter with two ceramic monoliths fitted side by side in one housing. Its advantages were high long-term stability, reduced exhaust gas backpressure and low noise emissions from the exhaust system. The evaporation gases from the fuel tank were trapped by an activated charcoal filter and mixed with the combustion gases at specified intervals. Over and beyond that, a number of features have been incorporated which reduce pollutant emission as early as during the combustion process. Among these is an air pump which during the warm-up phase channels fresh air through the cylinder head thus provided for the afterburning of unburnt hydrocarbons (HC) and carbon monoxide (CO) directly at the exhaust valves. An important contribution towards improved emission quality is rendered by the new mechanical/electronic CIS-E-V injection system. Among other things, it caused the oxygen sensor to be heated, monitors exhaust gas recirculation as well as secondary air injection, and controls the venting of the activated charcoal container.
R129 seats - more than just a car seat
With the SL, Mercedes-Benz introduced a completely new type of seat. This integral seat incorporated many features which not only enhance comfort but also increased passive safety. The following functions are integrated in the electrically adjustable seat:
- three-point inertia-reel seat belt;
- belt tensioner;
- seat belt sash guide height adjustment;
- head restraint height adjustment.
The adjustment of head restraint and sash guide height was coordinated. This ensured that the belts fit optimally, thus increasing occupant protection. The belt tensioner, which in the event of an accident pulled the belt tight within fractions of a second, was a standard fitting.
All these features combined into a comprehensive passive safety system, ranging from the front end structure specially designed to gave maximum protection in an offset frontal collision to the new, automatically extended roll-over bar system which needed not fear comparison with the saloons.
Sporty handling and ride comfort as required
The most important contribution to active safety was rendered by good handling and ride characteristics. The SL was fitted with the shock absorber strut independent front suspension and the multi-link independent rear suspension, a combination which had already proved its outstanding qualities in other Mercedes-Benz car series. In addition, all SL models including for the first time the six-cylinder models was optionally available with acceleration skid control (ASR). In combination with the standard ABS and electronic engine control, this ensured optimum traction and maximum safety reserves even under difficult road surface conditions.
A completely new feature on the convertible was the adaptive damping system (ADS) which was combined with automatic level adjustment and control. On the move, ADS permanently adjusts the damper characteristics to the prevailing driving and road conditions. The system changed from one damper setting to another there was altogether four fully automatically and imperceptibly. With this innovative technology on 89, the previously conflicting targets of ride comfort and sporty handling have been reconciled. The electronics always and accurately provided for the suspension characteristics which was most appropriate for the motoring style, driving situation or road condition at any given point in time.
Ultra-modern production facilities in Bremen on 89
For the first time, a Mercedes-Benz SL was manufactured in Bremen. In conjunction with Mercedes-Benz's knowhow in sports car manufacture, highly modern production facilities ensured that the most exacting quality standards was met for the convertible. The quality of the new SL could only be achieved by means of the use of the most advanced production technology when it comes to torsional rigidity, dimensional accuracy, the passive safety of the car's structure and all other aspects relevant to quality. Up until then, this degree of scrupulousness has not been conceivable in view of the production volume of the luxury sports car. It was planned to produce some 2,000 convertibles per year in Bremen once production run in full swing. Being an export harbour and thus a link with all countries around the world, the former hanseatic city of Bremen was a particularly good location in which to proceed the international SL myth.
Integral all-steel body, open, with detachable hardtop.
Fronta axle: Shock absorber strut independent front suspen- sion with anti-dive control, coil springs on wishbones, gas-filled shock absorbers, negative steering offset, torsion bar stabilizer.
Rear axle: Multi-link independent rear suspension with anti-squat and anti-lift controls, coil springs, gas-filled shock absorbers, torsion bar stabilizer, Level control all round, and electronically controlled damping system (ADS) available as optional extra.
Brake system: Hydraulic two-circuit brake system with vacuum brake booster, 4-piston fixed caliper disc brakes, ventilated, front 2-piston fixed caliper disc brakes, rear anti-lock braking system (ABS).